The present application is related to survivable hybrid optical/electrical data center networks using loss of light detection.
Following the trend of upgrading electrical cables and transceivers to optical fiber cables and transceivers, data center networks (DCNs) are transitioning from all-electrical networks to hybrid electrical/optical networks or all optical networks. However, conventional systems do not address the survivability issues in DCNs appropriately. Generally speaking, the multi-stage distributed architectures with a lot of equal-cost paths between end hosts are more robust to network failures and can provide alternative routes when one or more link/node fails. On the other hand, the single stage architectures rely on a single device or components to accomplish the switching task, therefore they are more vulnerable to network failures (if the switching device fails, the whole network fails). Another aspect of the survivability issue is failure detection. In the all-electrical DCNs, failure detection is intrinsic, since each electrical transceiver either has the capability of detecting port/link failures or can be programmed to do so. While in the optical DCNs, whether it is the all-optical DCNs or the optical embodiment of the hybrid DCNs, the optical switches providing the traffic bypassing capabilities (i.e. any electrical processing is bypassed) in the network are not capable of detecting link or port failures, simply because the “loss-of-light” event cannot be detected until the signals reach the end optical receivers. One reason that the current optical switches do not want to detect the “loss-of-light” event is that such detection causes the additional loss of optical power, while the major optimization goal of an optical switch is to minimize the insertion loss. Therefore, any tapping-off of the optical power for detection purpose was not considered.